using System;
using System.Collections.Concurrent;
using System.Windows.Forms;
using PolyTraderSharp.Services;

namespace PolyTraderSharp.Ui.Views
{
    /// <summary>
    /// Terminal-/Log-Ansicht. Designbar (siehe TerminalView.Designer.cs). Die Laufzeit-
    /// Abhängigkeit (TerminalLogger) wird per <see cref="Initialize"/> injiziert, damit der
    /// parameterlose Konstruktor für den VS-Designer nutzbar bleibt.
    /// </summary>
    public partial class TerminalView : Form
    {
        private TerminalLogger? _logger;
        private readonly ConcurrentQueue<LogMessageEventArgs> _logQueue = new();
        private readonly System.Windows.Forms.Timer _uiLogTimer = new() { Interval = 250 };
        private bool _autoScroll = true;
        private EventHandler<LogMessageEventArgs>? _logHandler;

        public TerminalView()
        {
            InitializeComponent();

            // Steuerelemente + statische Eigenschaften stammen aus dem Designer.
            // Hier nur noch Verhalten verdrahten und einen sinnvollen Default wählen.
            if (cbLogLevel.Items.Count > 0) cbLogLevel.SelectedIndex = 0;
            btnAutoscroll.Click += (_, _) => ToggleAutoscroll();
            _uiLogTimer.Tick += ProcessLogQueue;
        }

        /// <summary>Verbindet die View mit dem Logger (Laufzeit-DI).</summary>
        public void Initialize(TerminalLogger logger)
        {
            _logger = logger;

            // Jüngste Historie vorladen, damit das Fenster beim Öffnen nicht leer ist.
            foreach (var e in _logger.GetHistory(TimeSpan.FromMinutes(10)))
                _logQueue.Enqueue(e);

            _logHandler = (_, e) => _logQueue.Enqueue(e);
            _logger.OnLogMessage += _logHandler;

            _uiLogTimer.Start();
            Disposed += OnDisposed;
        }

        private void OnDisposed(object? sender, EventArgs e)
        {
            _uiLogTimer.Stop();
            if (_logger != null && _logHandler != null)
                _logger.OnLogMessage -= _logHandler;
        }

        private void ToggleAutoscroll()
        {
            _autoScroll = !_autoScroll;
            btnAutoscroll.BackColor = _autoScroll ? System.Drawing.Color.LightGreen : System.Drawing.Color.IndianRed;
            btnAutoscroll.Text = _autoScroll ? "Stop Autoscroll" : "Start Autoscroll";
        }

        private void ProcessLogQueue(object? sender, EventArgs e)
        {
            if (_logQueue.IsEmpty || !IsHandleCreated) return;

            string filter = cbLogLevel.SelectedItem?.ToString() ?? "Alle";
            TimeZoneInfo berlinTz = TimeZoneInfo.FindSystemTimeZoneById("W. Europe Standard Time");
            bool appended = false;
            int count = 0;
            const int maxProcess = 500;

            rtbTerminal.SuspendLayout();

            while (count < maxProcess && _logQueue.TryDequeue(out var logEvent))
            {
                count++;
                if (filter != "Alle" && logEvent.Level.ToString() != filter) continue;

                DateTime logTime = logEvent.Timestamp.Kind == DateTimeKind.Utc
                    ? TimeZoneInfo.ConvertTimeFromUtc(logEvent.Timestamp, berlinTz)
                    : TimeZoneInfo.ConvertTime(logEvent.Timestamp, berlinTz);
                string timeStr = $"[{logTime:HH:mm:ss}]";

                System.Drawing.Color c = System.Drawing.Color.White;
                if (logEvent.Level == LogLevel.Error) c = System.Drawing.Color.Red;
                else if (logEvent.Level == LogLevel.Warning) c = System.Drawing.Color.Yellow;
                else if (logEvent.Level == LogLevel.Trade) c = System.Drawing.Color.LightGreen;
                else if (logEvent.Level == LogLevel.TradeReasoning) c = System.Drawing.Color.Orange;

                rtbTerminal.SelectionStart = rtbTerminal.TextLength;
                rtbTerminal.SelectionLength = 0;
                rtbTerminal.SelectionColor = c;
                rtbTerminal.AppendText($"{timeStr} [{logEvent.Level}] {logEvent.Message}\n");
                appended = true;
            }

            if (appended)
            {
                if (rtbTerminal.TextLength > 80000)
                {
                    rtbTerminal.Clear();
                    rtbTerminal.SelectionColor = System.Drawing.Color.LightPink;
                    rtbTerminal.AppendText($"[{DateTime.Now:HH:mm:ss}] [System] Terminal Auto-Clear (RAM Limit erreicht). Vollständige Logs im Ordner /Logs.\n");
                }

                if (_autoScroll) rtbTerminal.ScrollToCaret();
            }

            rtbTerminal.ResumeLayout();
        }
    }
}